Cutting tool



Deg. 5, 1944. o, c. MARTIN 2,364,305

CUTTING TOOL Original Filed April 20, 1940 Arron/may i Patented Dec. 5, 1944 CUTTING TOOL one 0. Martin, Los Angeles, Calif.

Original application April 20, 1940, Serial No.

Divided and this application March 16, 1942, Serial No. 434,811

(Cl. Tl-53) 7 Claims.

My invention relates to a boring or forming tool and has particular reference to a boring or forming tool which is particularly adapted to themanufacture of'fluid control valve bodies.

This application is a division of my copending application Serial No. 330,752,filed April 20, 1940, and entitled Method and apparatus for manufacturing valve bodies.

In my copending application Serial No. 323,- 376, filed March 11, 1940 and issued as Patent No. 2,279,693 on April I l, 1942, entitled Valve, I have described and claimed a novel fluid valve construction which is particularly adapted for use in air craft for controlling various types of fluid power apparatus. The particularly notable advantages inherent in this new valve reside in its small size, light weight, and inexpensive construction. The present invention is directed to certain tools by means of which this new valve may be readily and inexpensively constructed.

Valves of the character disclosed in my aforementioned copending application Serial No. 323,- 376 employ a plurality of bores and chambers, a part of which are used to house valve members and a part of which constitute fluid entrance and exit openings. These bores and chambers are provided with various enlargements which function as fluid passages, and oer tain of these are disposed in intersecting relation with enlargements of adjacent bores to provide a fluid intercommunication between bores.

Prior to my invention these bores and enlarge- -ments had to be formed of destructible cores employed in connection with the casting of cast valve bodies or, in the caseof valves requiring a valve body of greater strength and higher quality than could be obtained by casting, by means of boring tools requiring the use of a separate tool for each bore and enlargement thereof and frequently requiring a separate and distinct set up of the boring machine for each operation. Such methods of manufacture are expensive and time consuming.

It is therefore an object of my invention to provide a boring tool for use in the manufacture of valves of the character set forth hereinbefore.

It is also an object of my invention to provide a boring tool comprising a 'tool shank and a laterally extending cutting element in which the cross sectional shape of the shank is so proportioned with respect to the diameter of the bore enlargement to be formed by the tool as to provide the maximum possible amount of material in the shank.

It is. another object of my invention to provide a tool of the character set forth in the preceding paragraphs in which the shank portion is formed with a lenticular cross section.

It is an additional object of my invention to provide a tool of the character set forth in the preceding paragraph in which the lenticular cross section is defined by eccentrically disposed cylindrical surfaces each having a radius of curvature substantially equal to the radius of the pilot bore in which the tool is to be used.

Other objects and advantages of my invention will be apparent from a study of the following specifications, read in connection with the accompanying drawing, wherein:

Fig. 1 is a fragmentary sectional view illustrat ing the manner in which a boring tool of my invention may be employed for providing enlargements in the pilot bores formed in a valve body;

Fig. 2 is a cross sectional view illustrating the manner in which tools of the character shown in Fig. 1 are received in their respective bores prior to the commencement of a boring operation;

Fig. 3 is a view similar'to Fig. 2 but illustrating the position of the tools at the conclustion of the boring operation; and

Fig. 4 is a cross sectional view of the shank of a boringtool of my invention.

I have illustrated in the accompanying drawing the use of the tool of my invention as directed to the forming of a valve body of the character used in a valve such as that disclosed and claimed in my copending application Serial No. 323,376, filed March 11, 1940, entitled Valve. The valve which is disclosed in that application employs a valve body I (see Fig. 1) within which is provided a discharge port 3 and a valve chamber bore 5. The discharge bore 3 is provided at its lower end with an enlargement 8 which intersects a similarly disposed enlargement 1 formed in the valve chamber bore 5.

The enlargements l and 8. which are to be formed at the lower ends of the bores 3 and 5 may be conveniently bored by means of a boring tool such as that illustrated in the drawing This tool preferably comprises a bar portion Madapted to be carried in the tool carriage of a suitable boring machine or engine lathe. The bar l4 bears on its outermost end a shank portion l5 which terminates in a cutter portion 56.

The block I is mounted for rotation about the axis of the bore to be enlarged (such as the bore 3 in Fig. 1) as by clamping the block I securely to the face plate min a chuck of an engine lathe. The bar portion I4 is suitably mounted on the tool carriage of the lathe and the carriage is moved to such position as to insert the tool within the bore 3 to the desired depth. The block I is then rotated and the tool is moved laterally relative to the axis of rotation of the block I so as to bring the cutter portion [6 thereof into engagement with the walls of the bore and remove the material therefrom to provide the enlargement 8.

The manner in Which the tool is constructed is illustrated in Fig. 4 wherein the cutter portion l6 and the shank portion l are illustrated as being formed integrally with each other and integrally with the bar portion I4. In employing this method of manufacturing the tool, a bar portion [4 of any desired size is first turned as by means of a lathe to a cylinder having a diameter slightly smaller than the diameter of the bore 3 or 5 in which the tool is to be used as is indicated by the dotted line I! in Fig. 4 and having a length somewhat in excess of the depth of the bore 3 or 5. This cylindrical portion may be formed in a lathe by rotating the bar [4 about its longitudinal axis indicated by reference character IS in Fig. 4. The shank portion [5 is then formed by cutting away the material from one side of the cylindrical portion IT. This may be done by mounting the cylinder I! for rotation in a lathe about an axis such as that indicated at IS in Fig. 4 and cutting the material by means of a lathe tool along a surface which is concentrically disposed relative to the axis l9 and which has a radius of curvature equal to the radius of the cylindrical portion l1.

Since it is desired to retain a maximum amount of material to serve as the shank portion ii in order that the strength thereof may be maintained at a maximum, the offset between the axes I 8 and I9 is soadjusted as to permit the surface 20 to be brought into contact with the sides of the bore 3 or 5 at the time the tip of: the cutter 16 has reached its maximum lateral penetration to form the enlargement I or 8. The offset between the axes l8 and I9 will be found to be equal to one-half the difference in diameter between the bore in which the tool is to be inserted and the diameter of the enlargement to be cut the-rein. For example, if it is desired to cut a one inch diameter enlargement in a diameter bore, the offset between the axes l8 and [9 will be s of an inch or one-half of the difference between one inch and of an inch.

I have indicated by means of a dotted circle 2| in Fig. 4 the maximum permissible diameter which could be employed on the shank l5 if that shank were formed of cylindrical cross section. It will be observed that a substantial increase in the amount of material retained in the shank l5 is achieved by forming the shank with a lenticular cross section as above described, and attention is further directed to the fact that the long axis of this cross section is extended in the direction to best withstand the forces imposed thereon by the engagement of the cutter IS with the block I. After the shank I5 is formed, the upper part of the circular member remaining at the outermost end thereof is cut away along a line 2| a to provide an upper tool face having the proper rake to give whatever cutting angle is desired at the cutting edge 2lb of the cutter portion l6. Similarly, the underside of the cutter portion l6 preferably relieved along a surface Me to provide for the required clearance between the fiank of the tool and the work.

, I have illustrated in Fig. 2 the relation of the cutter l6 and the shank IS with the bore 3 or 5 at the time the cutter is inserted in the bore preparatory to cutting the enlargement 1 or 8. I have also illustrated in Fig. 3 the relationship between these parts at the time the cutting of the recess 1 or 8 is completed.

It will be apparent from the foregoing that I have provided a. novel boring tool and method of making the same which provides a maximum amount of material in the shank portion of the tool interconnecting the cutter with the supporting bar portion and that this shank material is disposed in such configuration as to achieve the maximum strength and rigidity.

While I have, in the foregoing, described as a use to which the tool of my invention is particularly adapted, the manufacture of a particular type of valve such as that disclosed in my aforementioned copending application, it will be readily apparent to those skilled in the art that the tool is also well adapted to the manufacture of valve bodies of various types and in fact to the forming of bores having enlargements and recesses in metal parts of various descriptions.

While I have shown and described the preferred embodiment of my invention, I do not desire to be limited to any of the details of construction shown or described herein, except as defined in the appended claims.

I claim:

1. A boring tool for cutting in a valve body an enlargement of a pilot bore provided therein which comprises: a bar member for clampingin the tool post of a machine tool; a longitudinally extending shank of lenticular cross section formed on the end of said bar member; and a laterally extending cutting element carried by said shank having an upper face intersecting a flank surface to form a cutting edge, said flank surface being substantially a continuation of one of the partially cylindrical surfaces forming the lenticular cross section of said shank.

2. A boring tool for cutting in a valve body an enlargement spaced from the outer end of a pilot bore provided therein which comprises: a bar member for clamping in the tool post of a machine tool; a longitudinally extending shank of lenticular cross section formed on the end of said bar member, said lenticular cross section.

being formed by oppositely directed partially cylindrical surfaces each having a radius of curvature substantially' equal to the radius of said pilot bore, whereby said shank may be inserted into said bore with one of said surfaces closely adjacent the surface of said pilot bore and subsequently moved laterally a distance sufficient to engage the other of said surfaces with the surface of said pilot bore; and a laterally extending cutting element carried by said shank having an upper face intersecting a flank surface to form a cutting edge, said flank surface being substantially a continuation of one of the partially cylindrical surfaces forming the lenticular cross section of said shank.

3. A boring tool for cutting in a valve body an enlargement spaced from the outer end of a pilot bore provided therein which comprises: a bar member for clamping in the tool post of a machine tool; a longitudinally extending shank of lenticular cross section formed on the end of said bar member, said lenticular cross section having a width substantially equal to the difi. In a boring tool for cutting in a body an enlargement spaced from the outer end of a pilot bore provided therein, a tool shank having a lenticular cross section defined by oppositely directed partially cylindrical surfaces each having a radius of curvature substantially equal to the radius of said pilot bore whereby said shank may be inserted into said bore with one of said surfaces closely adjacent the surface of said pilot bore and subsequently moved laterally a distance sufficient to engage the other of said surfaces with the surface of said pilot bore.

5. In a boring tool for cutting in a body an enlargement spaced from the outer end of a pilot bore provided therein, a tool shank having a lenticular cross section defined by oppositely directed partially cylindrical surfaces each having a radius of curvature substantially equal to the radius of said pilot bore, the longitudinal axes of said two partially cylindrical surfaces extending parallel to each other and parallel to the length of said shank, said axes being spaced aparta distance substantially equal to the difference between the radii of said pilot bore and said enlargement, whereby said shank may be inserted into said bore with one of said surfaces closely adjacent the surface of said pilot bore and subsequently moved laterally a distance equal to said difference in radii.

6. In a boring tool for cutting in a body an enlargement spaced from the outer end of a pilot bore provided therein, a tool shank having a lenticular cross section defined by oppositely directed partially cylindrical surfaces each having a radius of curvature substantially equal to the radius of said pilot bore, whereby said shank may be inserted into said bore with one of said surfaces closely adjacent the surface of said pilot bore and subsequently moved laterally a distance suflicient to engage the other of said surfaces with the surface of said pilot bore, and a laterally extending cutting element formed on the end of said tool shank.

'7. In a boring tool for cutting in a body an enlargement spaced from the outer end of a pilot bore provided therein, a tool shank having a lenticular cross section defined by oppositely directed partially cylindrical surfaces each having a radius of curvature substantially equal to the radius of said pilot bore, the longitudinal axes' of said two partially cylindrical surfaces extending parallel to each other and parallel to the length of said shank, said axes being spaced apart a distance substantially equal to the difference betweenthe radii of said pilot bore and said enlargement, whereby said shank may be inserted into said bore with one of said surfaces closely adjacent the surface of said pilot bore and subsequently moved laterally a distance equal to said difference in radii, and means on one end of said shank defininga cutting edge positioned substantially in the plane of said axes and spaced from the adjacent partially cylindrical surface a distance substantially equal to said difference between said radii, whereby said cutting edge will just clear the surface of said pilot bore as said shank is inserted therein.

OTIS C. MARTIN. 

